#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include <signal.h>

#define N 32
#define M 256

enum{
    L=0x1,  //登录
    C,  //聊天
};

typedef struct{
    int type;//消息类型
    char name[N];
    char text[M];//消息正文
}MSG;

#define LEN sizeof(MSG)

int main(int argc, const char *argv[])
{
    int sockfd;
    struct sockaddr_in serveraddr;
    MSG msg;
    pid_t pid;
    socklen_t len=sizeof(struct sockaddr);
    
    if(argc!=3)
	{
        printf("user:%s ip port",argv[0]);
        return -1;
    }

    //创建socket
    sockfd = socket(AF_INET, SOCK_DGRAM, 0);
    if(sockfd < 0)
	{
        perror("socket err");
        exit(-1);
    }

    //指定服务器地址
    bzero(&serveraddr,len);
    serveraddr.sin_family = AF_INET;
    serveraddr.sin_port = htons(atoi(argv[2]));
    serveraddr.sin_addr.s_addr = inet_addr(argv[1]);

    //输入用户名，并发给服务器登录信息
    puts("====================client login=================");
    msg.type = L;
    printf("input name:");
    gets(msg.name);
    sendto(sockfd, &msg, LEN, 0, (struct sockaddr *)&serveraddr, len);

    //fork--子进程发送，父进程接收
    pid = fork();
    if(pid < 0)
	{
        perror("fork err");
        exit(-1);
    }
	else if(pid == 0)
	{  //子进程
        while(1)
		{
            gets(msg.text);
            msg.type = C;
            sendto(sockfd, &msg, LEN, 0, (struct sockaddr *)&serveraddr, len);
        }
    }
	else
	{
        while(1)
		{
            recvfrom(sockfd, &msg, LEN, 0, (struct sockaddr *)&serveraddr, &len);
            puts(msg.text);
        }
    }

}
